Buildings.Templates.Components.Tanks

Tank models

Information

This package contains models for storage and buffer tanks.

Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).

Package Content

Name	Description
Buffer	Buffer tank

Buildings.Templates.Components.Tanks.Buffer

Buffer tank

Buildings.Templates.Components.Tanks.Buffer

Information

Model of a buffer tank based on the instantaneously mixed volume model Buildings.Fluid.MixingVolumes.MixingVolume. Manufacturers recommend tank designs that promote mixing (e.g., with inside baffle plates) because a fully mixed tank yields an effective buffer time greater than a stratified tank. The validation model Buildings.Templates.Components.Validation.Tanks shows that achieving the supply temperature at the tank outlet requires circulating a fluid volume several times greater than the tank's actual volume.

Extends from Buildings.Fluid.Interfaces.PartialTwoPortInterface (Partial model with two ports and declaration of quantities that are used by many models).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Volume	V		Volume [m3]
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Configuration
Boolean	have_tan	true	Set to true for tank, false for direct pass through
Assumptions
Boolean	allowFlowReversal	true	= false to simplify equations, assuming, but not enforcing, no flow reversal
Advanced
MassFlowRate	m_flow_small	1E-4*abs(m_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed
Dynamics
Conservation equations
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Type of energy balance: dynamic (3 initialization options) or steady state
Graphics
IntegrationPoint	icon_pipe	Buildings.Templates.Componen...	Pipe symbol

Connectors

Type	Name	Description
FluidPort_a	port_a	Fluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_b	port_b	Fluid connector b (positive design flow direction is from port_a to port_b)

Modelica definition

model Buffer "Buffer tank" extends Buildings.Fluid.Interfaces.PartialTwoPortInterface; parameter Boolean have_tan=true "Set to true for tank, false for direct pass through"; parameter Modelica.Units.SI.Volume V( start=0) "Volume"; // Assumptions parameter Modelica.Fluid.Types.Dynamics energyDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial "Type of energy balance: dynamic (3 initialization options) or steady state"; parameter Buildings.Templates.Components.Types.IntegrationPoint icon_pipe= Buildings.Templates.Components.Types.IntegrationPoint.None "Pipe symbol"; Buildings.Fluid.MixingVolumes.MixingVolume vol( redeclare final package Medium=Medium, final V=V, final m_flow_nominal=m_flow_nominal, final m_flow_small=m_flow_small, final energyDynamics=energyDynamics, final massDynamics=energyDynamics, final mSenFac=1, final allowFlowReversal=allowFlowReversal, nPorts=2) if have_tan "Tank"; Buildings.Templates.Components.Routing.PassThroughFluid pas( redeclare final package Medium=Medium, final allowFlowReversal=allowFlowReversal) if not have_tan "Direct pass through"; equation connect(port_a, vol.ports[1]); connect(vol.ports[2], port_b); connect(port_a, pas.port_a); connect(pas.port_b, port_b); end Buffer;